2.0 Analysis 2.1 Course Alteration In the area where the collision occurred, ships have to make course alterations totalling 40 degrees. In this case, the helmsman's job was to steer by the compass and carry out the course alterations ordered by the pilot and monitored by the apprentice, who was near the helmsman. The course was altered in stages from 270 to 250(T), and the operation was carried out by the helmsman without any difficulty. When the pilot ordered a course alteration from 250 to 240(T), the CICRO was on the port beam of the bulk carrier. At that time, the full attention of the bridge watch, including the helmsman, was focused on the CICRO. As a result, the ZIEMIA ZAMOJSKA strayed beyond the heading ordered by the pilot. 2.2 Inattention of the Bridge Watch on the ZIEMIA ZAMOJSKA The role of the OOW in the master's absence is to see to the safety of the vessel, monitor the pilot's actions and ensure that the helmsman carries out the wheel orders and steers the course ordered by the pilot. It appears that because the CICRO was close on the port beam of their vessel, the full attention of the bridge watch on the ZIEMIA ZAMOJSKA was focused on that vessel. 2.3 Effort of Concentration Some effort of concentration is required for a helmsman to maintain a desired course, particularly in a narrow channel, and especially on a curve with another vessel in an overtaking situation. Further, a less experienced helmsman has to make a greater effort of concentration to stay on course. 2.4 Hydrodynamic Effects Notwithstanding the magnitude of the forces induced by the hydrodynamic effect between the two vessels as the CICRO was overtaking the ZIEMIA ZAMOJSKA, the main reason for the bulk carrier straying off course was the lack of attention on the part of the helmsman and the bridge officers. The data from the course recorder show that the ZIEMIA ZAMOJSKA responded quickly to the helm once corrective action was taken. 3.0 Conclusions 3.1 Findings Because the CICRO was close on the port beam of their vessel, the full attention of the bridge watch on the ZIEMIA ZAMOJSKA was focused on that vessel. The pilot of the ZIEMIA ZAMOJSKA realized that the vessel was straying beyond the ordered heading when he noticed green buoy S27 coming up fast ahead of the vessel. The officer of the watch (OOW) on the ZIEMIA ZAMOJSKA was not monitoring the helmsman's actions and did not realize that the vessel had strayed beyond the heading ordered by the pilot. The data from the course recorder on the ZIEMIA ZAMOJSKA show that the vessel's heading went as far as 210 while the channel is oriented at 236. Because of the course recorder on the ZIEMIA ZAMOJSKA, it was possible during this investigation to determine the reason for that vessel's fast turn to port when the CICRO was passing her. The data recorded by the Racal Decca BridgeMaster unit on the CICRO were also useful to this investigation for establishing with certainty that the ro-ro cargo ship was on the south side of the channel as agreed. The last-minute collision avoidance action taken by the two vessels limited the damage. 3.2 Causes The CICRO and the ZIEMIA ZAMOJSKA collided when the ship being overtaken, the ZIEMIA ZAMOJSKA, strayed beyond the heading ordered by the pilot. The helmsman's error of inattention was not detected in time because the full attention of the bridge watch was focused on the overtaking vessel. The Board has no marine safety recommendations to issue at this time.4.0 Safety Action The Board has no marine safety recommendations to issue at this time.